docs: def get_previous_request(rid):
      """Return the last ceph broker request sent on a given relation
  
      @param rid: Relation id to query for request
      """
      request = None
      broker_req = relation_get(attribute='broker_req', rid=rid,
                                unit=local_unit())
      if broker_req:
          request_data = json.loads(broker_req)
          request = CephBrokerRq(api_version=request_data['api-version'],
                                 request_id=request_data['request-id'])
          request.set_ops(request_data['ops'])
  
      return request